Piezoelectric crystal



Nov. 6, 1945. R, K 2,388,596

PIEZOELECTRIC CRYSTAL Filed Jan. 9, 1943 E. E Beoo/cs 5 z TQ K Patented Nov. 6, 1945 PIEZOELECTRIC CRYSTAL Robert E. Brooks, Maywood, Ill., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application January 9, 1943 Serial No. 471,884

6 Claims.

This invention relates to piezoelectric crystals and more particularly to a mounting for piezoelectric crystals.

In the manufacture. of certain types of electronic communication equipment, it is sometimes the practice to employ quartz crystals as frequency control devices. The apparatus in which these crystals are used may sometimes be subjected to severe and frequent shocks which are transmitted to the crystal. Considerable strains .may thereby be placed on the crystal mounting which may be sufiicient to weaken or even .to rupture the mounting. a

An object of the present invention is to provide an eiilcient and effective mounting for piezoelectric crystals.

In accordance with one embodiment of this invention, a piezoelectric crystal mounting may be provided comprising a pair of semi-circular springs, one pair of ends of these springs being attached to lead wires on either side of the crystal, and the lobes of the springs extending in the same direction. The opposite ends of the springs are attached to oppositely disposed terminal members on the base of the crystal housing.

Other objects and advantages of this invention will be apparent from the following detailed description taken in conjunction with the drawing, wherein:

Fig. 1 is an enlarged perspective view of a crystal and mounting, and

Fig. 2 is an enlarged perspective view of the opposite side of the crystal.

A primary problem in the mounting of piezoelectric crystals resides in the difliculty in obtaining a durable bond between the lead wire and the crystal, the vibration and shocks to which the crystals are subjected frequently causing the lead wires to part from the crystal. Although a rigid clamp mounting would obviate this dimculty, for some purposes a resilient mounting is more desirable. However, with resilient mountings forces on the crystal mounting produced by various shocks may not move in the same direction and, thus, a tendency to produce a shearing or twisting action on the crystal mounting may be produced which may cause the lead wires to part from the crystal.

Referring now to the drawing, a quartz crystal I of standard design is shown having one of a pair of lead wires I and 1 extending perpendicularly from each of the sides thereof. The lead wires are soldered to the center or nodal point of the-crystal. One end of a semi-circular spring is soldered to the end of one lead wire 6, as

shown in Fig. 2, and the other end of the spring 8, which extends at a tangent to the base of a semicircular curve 9, formed therein, is attached to a terminal 10 extending through and aflixed to a crystal mounting or housing base II, which is made of suitable insulating material.

One end of a second spring l3, having a semicircular upper portion corresponding in shape and size to the semi-circular upper portion 9 of the spring 8, is attached to the end of the lead wire 1 which extends from the side of the crystal. As shown in Fig. 1, the spring I3 is so mounted that this semi-circular portion l4 extends in the same direction as the semi-circular portion 9 of the spring 8. However, instead of extending the base of the semi-circular portion I4 at a tangent thereto as in the spring 8 and connecting the end thereof to a terminal positioned on or near this tangent, the base of the spring 13 is bent backwards near the end of the semi-circular portion 14 to extend backwards substantially parallel to the housing base II and is attached to a second terminal l5 mounted thereon at the opposite end thereof from which the other terminal i0 is mounted. Thus, while the semi-circular portions of both springs extend in the same direction, the springs are attached to oppositely positioned terminals.

It has been found in practice that the shearing action sometimes encountered in resilient spring mountings for quartz crystals is largely avoided by the design described. This appears to be due to the similar shape and position of the semi-circular portions of the springs, whereby any force applied to the crystal tends to produce a corresponding thrust on either side of the crystal substantially equal in amount and identical in direction, thus reducing to a minimum strains on the lead wires anchors.

While but one embodiment of this invention has been shown and described, itwill be understood that many changes and modifications may be made therein without departing from the spirit or scope of the present invention.

What is claimed is:

i. A mounting for a piezoelectric crystal comprising a lead wire extending from either side of the crystal, to support the crystal springs attached to said lead wires to support said wires and said crystal, a crystal mounting base, a pair of oppositely positioned terminals in said base, one of said springs being semi-circular and having a base portion extending at a tangent to the semi-circular portion, said base portion connected to one of said terminals, and the other of said springs having a similarly shaped semi-circular portion, the base portion being bent backwards "to extendto and connect with the other of said terminals.

, 2. A mounting for a piezoelectric crystal comprising a leadfwire extending substantially perpendicularly from either side of the crystal, to

support thecrystal springs attached to said lead base portion being bent backwards to extend to the other of said terminals.

. 3. A mounting for a piezoelectric crystal comprising a lead wire extending from either side of the crystal, to support the crystal springs attached to said lead wires to support said wires and the crystal, a crystal mounting base, a pair of oppositely positioned terminals in said base, one of said springs having a semi-circular portion and a base portion extending at a tangent to said semi-circular portion, said base portion being connected to one of said terminals, and the other of said springs having a similarly shaped semicircular portion, the base being bent backwards to extend to theother of said terminals and the lobes of said springs extending in substantially the same direction.

4. A resilient mounting for piezoelectric crystals comprising a lead wire extending from either side of the crystal, a single lobe curved spring attached to each lead wire to support'the crystal,

the lobes of said springs extending in salami-mtially; the same direction, a crystal mounting having a pair of terminals positioned therein, and each of said springs being connected to one of said terminals the two springs with their lobes extending in the same direction being the sole support for the crystal between the lead wires and said terminals.

r 5. A resilient mounting for piezoelectric cryscrystal between the lead wires and the said terminals.

6. A resilient mounting for piezoelectric crystals comprising a lead wire extending from either side of the crystal, a single lobe curved spring attached to each lead wire, the lobes of said springs being in juxtaposition but spaced from each other and extending in substantially the same direction, a crystal mounting base having a pair of terminals mounted thereon, each of said springs being connected to one of said terminals, the two springs with their lobes extending in the same direction being the sole support for the crystal between the lead wires and said terminals.

ROBERT E. BROOKS.

CERTIFICATE OF CORRECTION.

Patent no. 2,588,596.

November 6, 1914.5.

RQBERT E. BROOKS.

Itis hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, second column, line 11.8, page 2, first column, lines 7 and 8, and same page and column, line 21, for "crystal, to support the crystal springs" read -cry stal to support the crystal, springs--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of March, A. D. 19b6,.

Leslie Frazer First Assistant Commissioner of Patents.

(Seal) 

